You have two great answers there already. (personally I would forget northern Chile.) 

The Only other place I would suggest is Nasca to fly over the lines although the town is nothing special and even overnight is too much. If you arrive in Nazca early morning you can book a flight get to airport, fly, and be back in town ready to head out by lunchtime. I'm envious, I'd be happy meandering around in the sacred valley between Cusco and Machu Picchu for a month. Stay in a small town called Ollantaytambo, It's magic. Suerte (good luck)

Hello, Kavitha:

Good choice to visit Cusco, Arechelogical Capital of South America. Close to Cuzco there is a beautiful place for visiting ; it is Tipón, where you don´t see many people like in Sacsaywaman, Kenco, Puca Pucara and Tombomachay circuit near to Cuzco. Another places is Moray, Urubamba, Ollantaytambo fortress; Machu Picchu Citadel, the universal emblematic sign of  Perú. You could walk up hill of Machu Picchu from a small town called Aguas Calientes. Perhaps you should do Salkantay Trek if you love to walk. This circuit is less expensive than the classic Inca Trail.

Also, if you continue to Arequipa, I recomend to you the natural areas in the Colca Canyon, visit  Waruro Waterfall at 4000 m, Llawar Hot Spring;  the very popular circuit is San Juan de Chuccho and Oasis Paraiso Ecolodge. Also there is another  places in the Colca Valley, Canocota, Sibayo

In Arequipa,  at surounding area as Yumina, Quequeña District, Sabandía District, very nice place if you love the nature. Rafting in the Chili River. In Cusco, rafting in the  Vilcanota River of Sacred Valley.

Well, if you need  specific information, I am here.

My kindest regards,

Andres Calcina

www.facebook.com/andrescalcina007

Hey Kavitha,

I've been to Peru twice, and it has stolen my heart in more ways than one. From Cusco, you could go into the jungle from Puerto Maldonado, which is really cool. You can do hiking here, and see a ton of really spectacular flora and fauna. I'm not sure what you are doing from Lima to Cusco, but Arequipa and the Colca Canyon is a pretty amazing area to explore for a few days. If you are crossing into Chile, I would recommend visiting San Pedro De Atacama desert. It is apparently the closest place on Earth to Mars, and it is some of the most beautiful and surreal scenery that I have ever seen. I kept a travel blog while I was traveling South America in 2014, so please feel free to pay it a visit and read what I did. It is My Love Affair with Travel at www.amandakingsmith.com.

Cheers,

Amanda

Do not stay in Lima more than 3 days... plan to spend more time in Cusco!